X-Git-Url: http://git.cascardo.eti.br/?a=blobdiff_plain;f=kernel%2Ftask_work.c;h=d513051fcca271e560eeb9e181373609cf83a65c;hb=fd363bd417ddb6103564c69cfcbd92d9a7877431;hp=6ab4842b00e8bb71db357e5933fc6c3b72669832;hpb=b325e04ea21081439f0f3e7fe1117e883a9031d8;p=cascardo%2Flinux.git

diff --git a/kernel/task_work.c b/kernel/task_work.c
index 6ab4842b00e8..d513051fcca2 100644
--- a/kernel/task_work.c
+++ b/kernel/task_work.c
@@ -29,7 +29,7 @@ task_work_add(struct task_struct *task, struct callback_head *work, bool notify)
 	struct callback_head *head;
 
 	do {
-		head = ACCESS_ONCE(task->task_works);
+		head = READ_ONCE(task->task_works);
 		if (unlikely(head == &work_exited))
 			return -ESRCH;
 		work->next = head;
@@ -57,6 +57,9 @@ task_work_cancel(struct task_struct *task, task_work_func_t func)
 	struct callback_head **pprev = &task->task_works;
 	struct callback_head *work;
 	unsigned long flags;
+
+	if (likely(!task->task_works))
+		return NULL;
 	/*
 	 * If cmpxchg() fails we continue without updating pprev.
 	 * Either we raced with task_work_add() which added the
@@ -64,8 +67,7 @@ task_work_cancel(struct task_struct *task, task_work_func_t func)
 	 * we raced with task_work_run(), *pprev == NULL/exited.
 	 */
 	raw_spin_lock_irqsave(&task->pi_lock, flags);
-	while ((work = ACCESS_ONCE(*pprev))) {
-		smp_read_barrier_depends();
+	while ((work = lockless_dereference(*pprev))) {
 		if (work->func != func)
 			pprev = &work->next;
 		else if (cmpxchg(pprev, work, work->next) == work)
@@ -95,7 +97,7 @@ void task_work_run(void)
 		 * work_exited unless the list is empty.
 		 */
 		do {
-			work = ACCESS_ONCE(task->task_works);
+			work = READ_ONCE(task->task_works);
 			head = !work && (task->flags & PF_EXITING) ?
 				&work_exited : NULL;
 		} while (cmpxchg(&task->task_works, work, head) != work);